Resin composition, insulated electric wire and method of manufacturing insulated electric wire

Abstract

An insulated electric wire includes a conductor and an insulating layer coated in periphery of the conductor. The insulating layer is made of a resin composition containing a base polymer and a flame retardant. The flame retardant is made of silane-treated aluminum hydroxide, aluminum hydroxide treated with a treatment agent other than a silane coupling agent and/or untreated aluminum hydroxide. The base polymer contains a polymer having a polar group. The resin composition contains the flame retardant, a content of which is more than 40 parts by mass and equal to or less than 80 parts by mass per 100 parts by mass of the base polymer. The resin composition contains the silane-treated aluminum hydroxide, a content of which is equal to or more than 10 parts by mass and equal to or less than 70 parts by mass per 100 parts by mass of the flame retardant.

What is claimed is: 
     
       1. A resin composition comprising:
 a base polymer; and 
 a flame retardant, 
 wherein the flame retardant is made of aluminum hydroxide, a surface of which is treated with a silane coupling agent, and aluminum hydroxide, a surface of which is treated with a fatty acid, 
 the base polymer contains a polymer having a polar group, 
 the resin composition contains the flame retardant, a content of which is more than 40 parts by mass and equal to or less than 80 parts by mass per 100 parts by mass of the base polymer, and 
 the resin composition contains the aluminum hydroxide, a surface of which is treated with the silane coupling agent and a content of which is equal to or more than 10 parts by mass and equal to or less than 70 parts by mass per 100 parts by mass of the flame retardant. 
 
     
     
       2. The resin composition according to  claim 1 ,
 wherein the polymer having the polar group is ethylene-vinyl acetate copolymer. 
 
     
     
       3. The resin composition according to  claim 1 ,
 wherein the resin composition further contains a black, yellow, white, red or green colorant. 
 
     
     
       4. An insulated electric wire comprising:
 an insulating layer made of the resin composition according to  claim 1 . 
 
     
     
       5. A cable comprising:
 a sheath layer made of the resin composition according to  claim 1 . 
 
     
     
       6. The insulated electric wire according to  claim 4 ,
 wherein an oxygen index is equal to or larger than 20, and a tensile strength in 100% tension is equal to or smaller than 6.0 MPa. 
 
     
     
       7. The insulated electric wire according to  claim 4 ,
 wherein the insulated electric wire is used for an in-board wiring of a distribution board or a control board or for a motor lead wire. 
 
     
     
       8. A method of manufacturing an insulated electric wire comprising the steps of:
 (a) forming a resin composition by kneading a base polymer and a flame retardant; 
 (b) manufacturing an uncross-linked insulated electric wire by extruding the resin composition so as to coat periphery of a conductor to form an insulating layer; and 
 (c) manufacturing a cross-linked insulated electric wire by cross-linking the base polymer in the resin composition, 
 wherein the flame retardant is made of aluminum hydroxide, a surface of which is treated with a silane coupling agent, and aluminum hydroxide, a surface of which is treated with a fatty acid, 
 the base polymer contains a polymer having a polar group, 
 the resin composition contains the flame retardant, a content of which is more than 40 parts by mass and equal to or less than 80 parts by mass per 100 parts by mass of the base polymer, and 
 the resin composition contains the aluminum hydroxide, a surface of which is treated with the silane coupling agent and a content of which is equal to or more than 10 parts by mass and equal to or less than 70 parts by mass per 100 parts by mass of the flame retardant. 
 
     
     
       9. The method of manufacturing the insulated electric wire according to  claim 8 ,
 wherein, after the step (b) and before the step (c), the method includes a step of (d) reeling up the uncross-linked insulated electric wire. 
 
     
     
       10. The method of manufacturing the insulated electric wire according to  claim 8 ,
 wherein the cross-linked insulated electric wire has an oxygen index that is equal to or larger than 20, and has a tensile strength in 100% tension that is equal to or smaller than 6.0 MPa.